html {
  color-scheme: light;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: #f6f7f4;
  color: #20251f;
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  line-height: 1.6;
}

a {
  color: inherit;
}

.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: 1080px;
  margin: 0 auto;
  padding: 24px;
}

.brand {
  font-weight: 700;
  text-decoration: none;
}

nav a {
  color: #5f665e;
  font-size: 0.95rem;
  text-decoration: none;
}

main {
  max-width: 1080px;
  margin: 0 auto;
  padding: 24px 24px 72px;
}

.intro {
  max-width: 760px;
  padding: 56px 0 34px;
}

.eyebrow,
.meta {
  color: #607066;
  font-size: 0.86rem;
  font-weight: 700;
  letter-spacing: 0;
  text-transform: uppercase;
}

h1,
h2,
h3,
p {
  margin-top: 0;
}

.intro h1 {
  font-size: clamp(2.45rem, 6vw, 5rem);
  line-height: 0.98;
  max-width: 880px;
}

.intro p:last-child,
.featured p {
  color: #48534b;
  font-size: 1.12rem;
  max-width: 720px;
}

.featured {
  border-top: 1px solid #d5ddd5;
  border-bottom: 1px solid #d5ddd5;
  padding: 32px 0;
  margin: 18px 0 34px;
}

.featured h1 {
  font-size: clamp(1.75rem, 4vw, 3.2rem);
  line-height: 1.05;
  margin-bottom: 14px;
}

.button {
  display: inline-flex;
  align-items: center;
  min-height: 40px;
  padding: 0 16px;
  background: #20251f;
  color: #ffffff;
  font-weight: 700;
  text-decoration: none;
}

.article-tabs {
  font-size: 0;
  margin-top: 34px;
}

.tab-input {
  position: absolute;
  opacity: 0;
  pointer-events: none;
}

.tab-label {
  display: inline-flex;
  align-items: center;
  font-size: 1rem;
  min-height: 42px;
  padding: 0 18px;
  border: 1px solid #c9d4cb;
  color: #4e5a52;
  cursor: pointer;
  font-weight: 700;
}

.tab-label:first-of-type {
  border-radius: 6px 0 0 6px;
}

.tab-label:last-of-type {
  border-left: 0;
  border-radius: 0 6px 6px 0;
}

#tab-practice:checked + .tab-label,
#tab-primitive:checked + .tab-label {
  background: #235f52;
  border-color: #235f52;
  color: #ffffff;
}

.tab-panels {
  font-size: 1rem;
  margin-top: 26px;
}

.tab-panel {
  display: none;
}

#tab-practice:checked ~ .tab-panels .tab-panel-practice,
#tab-primitive:checked ~ .tab-panels .tab-panel-primitive {
  display: block;
}

.section-heading {
  max-width: 720px;
  margin-bottom: 22px;
}

.section-heading h2 {
  font-size: clamp(1.65rem, 3vw, 2.4rem);
  line-height: 1.08;
  margin-bottom: 10px;
}

.section-heading p:last-child {
  color: #48534b;
  font-size: 1.04rem;
}

.article-list {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 18px;
}

.article-card {
  background: #ffffff;
  border: 1px solid #d7ddd6;
  border-radius: 6px;
  padding: 22px;
}

.article-card h2,
.article-card h3 {
  font-size: 1.3rem;
  line-height: 1.15;
}

.article-card h2 a,
.article-card h3 a {
  text-decoration-thickness: 1px;
  text-underline-offset: 4px;
}

.article-card p {
  color: #4f5a52;
}

.article-page {
  max-width: 740px;
  margin: 44px auto 0;
  background: #ffffff;
  border: 1px solid #d7ddd6;
  border-radius: 6px;
  padding: clamp(24px, 6vw, 56px);
}

.article-page h1 {
  font-size: clamp(2rem, 5vw, 3.7rem);
  line-height: 1.02;
}

.article-page p {
  font-size: 1.08rem;
}

@media (max-width: 640px) {
  .site-header {
    padding: 18px;
  }

  main {
    padding: 12px 18px 48px;
  }

  .intro {
    padding-top: 36px;
  }

  .tab-label {
    justify-content: center;
    width: 50%;
    padding: 0;
  }
}